The world has serious concerns over fiscal crises, security crises and environmental crises including climate change.

And then there are vacations. Yes, vacations - the getaways when we can put aside lofty concerns and remember what living is all about: seeing friends, hosting family reunions, discovering a new artist at a provincial festival and running barefoot on the beach with salt air stinging our cheeks.

At least that was the definition of a vacation before globalization took off.

Now vacations have joined the ranks of the biggest global industrial complexes. While few noticed, travel and tourism grew into a giant business sector and the world's largest employer - beating out health care, education and retail. At least one out of every 11 people works in the industry, according to the World Travel and Tourism Council.

Tourism contributes at least US$6.5 trillion to the world economy every year. Since the 2008 recession, its growth rate has rebounded faster than manufacturing and financial services. And if frequent-flyer miles were a currency, they would be the most valuable in the world, even with all those blackout dates.

It turns out that tourism is the poster child for how to benefit from the global marketplace, for obvious reasons. Wholesale travel and tourism depends on open borders. With political developments and technology - new long-distance airliners that cross half of the globe in a single flight and the internet revolution - countries off the beaten path in South America, Africa and the Middle East are more accessible.

A chart of the rise of international tourist trips is a thumbnail history of globalization.

The modern era of "Europe on five dollars a day" began in 1960. That year 25 million trips were taken across foreign borders. Ten years later the figure rose to 250 million, a significant increase but not earth-shattering.

Then came globalization and the opening of borders. The end of the Cold War in the early 1990s accomplished just that - opening long closed borders in Eastern Europe and Asia, a wide swath of nations behind what used to be called the Iron Curtain and the Bamboo Curtain. This newly opened territory represented nearly one third of the planet, and by 1995, when most had opened up to tourism, there were 536 million trips.

Last year, the 1 billion mark was broken with the UN World Tourism Organization celebrating the event at its Madrid headquarters.

I dissect and explore this explosion of the tourism industry in Overbooked. The elusive octopus-like industry is everywhere and nowhere. Everyone takes vacations, but few see the industry behind them. Nowadays, any endeavor can be transformed into a travel package.

Take medical tourism, for example. Countries like Malaysia have brought together teams from their ministries of health and tourism to offer deals including airline travel, medical procedures and resort-style recuperation in the sun - all at a bargain-basement price compared to the health-care costs in the US.

The religious pilgrimage is the oldest reason for travel, and today the Hajj is the world's biggest travel event. Predominantly Muslim countries from Bangladesh to Indonesia have powerful ministries of Hajj that broker precious permission for citizens to travel to Saudi Arabia. The tourism industry has transformed the center of the holy site in Mecca. Old rest houses and buildings that once defined the traditional character of Mecca have been bulldozed and replaced by luxury skyscraper hotels and condominiums, a shopping mall and a clock tower that bears a striking resemblance to London's Big Ben.

So many billions of dollars are spent on the Hajj - the pilgrims spent US$16.5 billion last year in Saudi Arabia - that corruption is a temptation. In the middle of war, the Afghan minister of Hajj and pilgrimage fled the country rather than face charges he embezzled US$700,000 in Hajj funds.

The impacts of tourism and travel on the environment, culture and society are enormous. Hordes of day-trippers have transformed beautiful cities like Venice, where 20 million tourists visit a town of 60,000. Rents have skyrocketed as international chains compete for prime spots to capture the tourist dollar, forcing out locals from apartments along with green grocers, butchers and artisans. Venetian glass, paper and masks are now often made in China or Eastern Europe. Several activist groups of Venetians decry their politicians for failing to control the number of cruise ships or enforce regulations that restrict the expansion of hotel rooms. Even UNESCO has warned that Venice is as much danger of drowning from tourism as Aqua Alta.

The environmental costs can be high as well. Cruise ships, for instance, are notorious polluters. According to the Environmental Protection Agency, in the course of one day, the average cruise ship produces: 21,000 gallons of human sewage, one ton of solid waste garbage, 170,000 gallons of wastewater from showers, sinks and laundry and 8,500 plastic bottles. Major cruise lines are headquartered in the United States, but avoid major environmental regulations, as well as many taxes, by registering and flagging their ships in foreign countries.

Every traveler has a story about a favorite spot transformed by tourists who leave chaos and waste in their wake and government officials who prefer to count short-term benefits of allowing chock-a-block hotels over the long-term costs of environmental degradation.

Not surprisingly, France and Costa Rica are two countries that understood early on tourism's potential and the safeguards required to ensure that tourism enhanced their communities and national treasuries. But few would have guessed that Deng Xiaoping would be among tourism's early proponents. In late 1978, as he was preparing to consolidate power in China, Deng gave five "direction talks" on the central role tourism might play in China's reform movement.

For Deng, tourism was a natural to earn China much-needed foreign cash - he predicted US$10 billion a year by the new millennium, and China reached that goal in 1996. He viewed tourism as an effective way to flip negative impressions of China. While he didn't use the phrase "public diplomacy," he set into place a system to create a state-controlled tourism sector that includes government-trained tourist guides extolling the joys of the open market and China. Deng even calculated that if China brought tourism to Tibet it could influence international opinion, ensuring that Tibet remained in China's orbit. He also rightly warned that pollution from rapid industrialization could despoil the beautiful spots that would attract tourists.

When first reporting on this stealth industry and its downsides in 2008, I was accused of threatening everyone's right to travel. "Elitist" was the milder of the epithets thrown my way. For the emerging middle class around the world, travel is a right of passage. Travel is the reward for hard work and proof that one has arrived. Yet every right comes with responsibility, and protecting the world's beauties would seem obvious by demanding that the industry respect local culture, heritage and the environment.

The destinations are in peril if the public, their governments and international institutions don't study travel's impacts and find safeguards to protect what's loved by all.

(Elizabeth Becker is a former New York Times correspondent and senior foreign editor at National Public Radio. Her most recent book is Overbooked: The Exploding Business of Travel and Tourism, Simon and Schuster. © 2013 Yale Center for the Study of Globalization)